1. Field of the Invention
The present invention relates to an integrated alignment and overlay mark and the method for checking an alignment accuracy using the integrated alignment and overlay mark; especially, the present invention relates to an integrated mark having an alignment marks and an overlay mark exposed in the same shot region.
2. Description of Related Art
For determining the exposure alignment between layers on the wafer in the semiconductor manufacturing processes, there are alignment mark(s) and overlay mark(s) formed on the each layer so as to check the alignment by comparing the relative positions of the features of the marks.
However, the alignment mark and overlay mark are individually formed in different shot region (exposed area). In other words, the layer of the wafer has two individual marks, one is alignment mark and the other is overlay mark, formed thereon. Because the two individual marks are formed on the scribe lane, the scribe lane occupies the limited wafer area too much to manufacture efficiently semiconductor die on the wafer. In other words, the wafer area is not efficiently used due to the large scribe lane with the two individual marks thereon. Furthermore, the large scribe lane results in the small manufacturing window and the manufacturing yield cannot be highly promoted. On the other hand, in the view point of the material cost, the large scribe lane results in high cost of wafer material and the manufacturing benefit is decreased.
Furthermore, in comparison of the alignment mark and the overlay mark, engineer assumes that there is no error between the two marks. In practice, because that the two marks are formed in the different shot region, the error exists in the different exposed performance. Therefore, the analyzed result cannot precisely represent the alignment accuracy between the layers. In other words, the parameter of the exposure equipment cannot be precisely and correctly calibrated.
Consequently, with regard to the resolution of defects illustrated hereinbefore, the inventors of the present invention propose a reasonably designed solution for effectively eliminating such defects.